URBAN DOGS: PETS OR PESTS?

Joan BeckCHICAGO TRIBUNE

Four in 10 families have at least one. They account for 5 percent of all hospital emergency room visits. They spread parasites, facilitate the breeding of flies, help humans recover from heart attacks and foster mental health.

And recently, among learned symposia about genetic engineering, the composition of comets, supercomputers, artificial intelligence and other scholarly significa and exotica, the American Association for the Advancement of Science took time at its annual meeting to look at the urban dog.

Pets greatly outnumber people in the nation`s urban houses, reported Alan M. Beck of the University of Pennsylvania`s Center for the Interaction of Animals and Society. Americans own 48 million dogs, 27 million cats, 25 million caged birds, 125 million small mammals and reptiles and more than one billion fish--at least 1.2 billion household pets.

Uncountable millions of other living creatures share our cities, if not our homes. Coyotes roam the edges of Los Angeles. Peregrine falcons have been released in New York, Washington, Baltimore, Norfolk, Boston and Los Angeles, where skyscrapers provide cliff-like updrafts for flight and pigeons an unlimited supply of food. Raccoons in growing numbers raid backyard garbage cans.

But nothing equals the emotional bond between dog and dog owner--not even the ample evidence of the nuisances that dogs commit and, in fact, are. Beck explained, ''A large head, with large eyes and shortened snout, tends to bring out the nurturing in almost everyone.''

Problems there are, however. Dogs are responsible for most animal bites. Americans report one million dog bites annually--only a small percentage of the true total. Of all visits to hospital emergency rooms, 5 percent are people bitten by a dog. A study several years ago estimated that each dog bite costs at least $100 for medical care alone, not counting observing or testing the dog for rabies.

Pooper-Scooper laws haven`t ended either the aesthetic or the health problems of canine waste disposal in urban areas. People and dogs ''share some common pathogens and are possible sources of mutual infection,'' noted Beck, who suspects research will turn up more specific connections. ''Such relationships undoubtedly exist and are part of the risk of intimacy between living creatures.''

Dog waste is one of the most common urban breeding grounds for flies, which carry many kinds of bacteria. It`s also a source of a substantial percentage of complaints to city health departments--and of friction between urban neighbors.

At least 1.5 percent of all Americans are allergic to dogs and cats, Beck estimated. That makes medical treatment tricky. Allergists figure that more than half of their patients don`t follow instructions to get rid of a pet to which they are allergic. Many who do suffer guilt feelings, emotional reactions or psychological trauma that may aggravate their medical condition. Dog owners and others also allow themselves mental blind spots about the role humane societies play. They are, in reality, primarily places for the disposal of unwanted pets (a great majority of the animals they kill are not strays but are brought in by their owners) and for taking on the ''collective guilt'' of society for doing away with them.

Solid evidence is also accumulating about the value of urban dogs. One study shows, for example, that pet owners have a considerably greater chance of surviving for a year after being hospitalized for a heart attack than do nonowners. Laboratory tests show the presence of a dog can lower blood pressure and reduce stress in children. Considerable success has been reported in using dogs for psychological therapy.

None of this matters to dog lovers. Dogs touch such a primordial core of emotions in so many people that no amounts of inconvenience or regulation or complaints from neighbors are likely to dissuade them from sharing their lives and habitat with pets. Few urban planners take into account the needs of dogs and dog owners. But given the symbiotic relationship between dogs and people for so many centuries, it is shortsighted--and unsanitary--not to do so.